This invention relates to a shedding apparatus and method and fabric-forming machine and method which uses pneumatically-controlled and individually-programmable heddles. The invention is intended both for retro-fit onto existing conventional flat-weaving looms and other types of fabric-forming machines, and for incorporation into fabric-forming machines which may hereafter be developed, including those which may be developed specifically for use with the invention according to this application.
The apparatus and method according to the invention has the capability to control the shedding motion of each end in the warp individually to achieve the same result as a Jacquard loom. The shedding motion is created by electronically controlling the distribution of air pressure with solenoid valves to individual heddles, rather than by electronically controlling mechanical levers, as is the present practice. The design of the invention described in this application provides solutions to a number of problems.
The shedding motion of conventional Jacquard looms is cam controlled. As the operational limit of these types of looms is about 600 picks (filling insertions) per minute (ppm), it follows that the time for one shedding motion is 100 milliseconds. This is a limiting factor in the operation of the loom, since the fabric cannot be produced any faster than filling can be inserted and integrated into the warp yarns.
In contrast, the shedding motion for the invention described in this application is on the order of 35-40 milliseconds or less. Thus, consistent with other operating parameters, loom speed could be increased to the range of 1500 ppm. In addition, the shed formation is electronically controlled independent from the motion of the filling insertion apparatus, for example, the rapier on a rapier loom. Since the shed formation is electronically controlled, the shed position can be changed without changing the filling insertion apparatus.
Jacquard looms also have shedding motions which weave patterns with three or four repeats across the fabric because of the complex lever system of the Jacquard head. The invention according to this application can control every single warp end individually, enabling the loom to weave patterns with one repeat across the fabric. The invention of this application also does not require a gantry to hold the Jacquard head. This saves considerable overhead space, and will permit many weaving installations with low overhead space in the weave room to convert to weaving Jacquard-type fabrics by using the shed-forming apparatus and method disclosed and claimed below. The invention of this application is readily useable with known computer-aided pattern design systems. Examples are the Viable Weavette manufactured by Viable Systems, Inc. of Medfield, Mass., and the Vision Automatic pattern system manufactured by Info Design of New York.
The invention of this application is also adaptable to many different types of fabric-forming machines. Such machines include looms-for example, rapier, projectile, air jet, water jet and shuttle looms. As will be apparent, the particular type of filling insertion system is unimportant to the proper functioning of a fabric-forming machine according to the invention of this application. It is believed that the invention will have application in various forms of fabric formation.
The heddle system of the invention according to this application is manufactured in one piece, thereby making replacement very simple.